21316091 has 2 divisors, whose sum is σ = 21316092. Its totient is φ = 21316090.

The previous prime is 21316063. The next prime is 21316109. The reversal of 21316091 is 19061312.

It is a happy number.

Together with next prime (21316109) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21316091 - 2⁶ = 21316027 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21316021) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10658045 + 10658046.

It is an arithmetic number, because the mean of its divisors is an integer number (10658046).

Almost surely, 2^21316091 is an apocalyptic number.

21316091 is a deficient number, since it is larger than the sum of its proper divisors (1).

21316091 is an equidigital number, since it uses as much as digits as its factorization.

21316091 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 324, while the sum is 23.

The square root of 21316091 is about 4616.9352388787. The cubic root of 21316091 is about 277.2697698120.

The spelling of 21316091 in words is "twenty-one million, three hundred sixteen thousand, ninety-one".